Draw on a piece of paper what you want. Do a diagram of the cross-section.

A lot of forging is simply beating it with a hammer to make the shape you want.

You can always make things smaller.

It's difficult to go the other way.

<img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//blink.gi f' class='bbc_emoticon' alt=':blink:' />

I calculate that you might be forgetting who you're talkin too here Mike. While most of us have the ability to think, I would venture to say that ... well at least I don't carry that too far. The thinking, that is.

Figuring the volume of the material and displacing that volume is fine as long as you have complete control of it and all. But it's my opinion that there's too many variables to impose that (any calculation) from one person to the next. You can figure volume and grind it to shape or you can forge the blade and then round the bolster by removing the corners with a grinder.

I would describe it as more of a forging process, because once you heat it and start hammering, it becomes a process.

By the way, a 1x1 can be turned into a rectangle as a part of the process. Let's say 3/4 x 1-3/16 or so. Then step the blade down from there and, of course, the tang as well.

I often "do the math" when choosing starting stock size for a blade. I use a rough and ready calculation, that seems to work well for me.

(I typically start with round drill rod, so I have to figure the volume calculation)

It all starts with what you want to end with, so lets take a 1.5" wide, .25" thick (spine), and 7 inch long blade. I take the length and add half of what my tang will be (usually 4" divided by 2 is 2") and figure what volume of steel I need.

I always have a little extra built in to this formula because the blade is not .25" thick across the whole width. This accounts for some loss in the forging and a little more for grinding away.

So 7+2=9 x 1.5= 13.5 x .25= 3.375 So let's just call it 3.5 cubic inches of volume in the finished forging.

What size is your square bar? If it's 1" square, that's easy-peasy. There is 1 cubic inch per inch length of bar. So you need 3.5" of 1" square bar.

If you are starting with 3/4" square bar, the volume per inch length is .75 x.75= .5625. Now divide the 3.5 cubic inches by .5625 and you get 6.222. You would need 6.25 inches of 3/4" square bar.

For the integral bolster, I would just add the volume of the bolster into the finished calculation.

It's always good to think about the finished width in comparison to the starting stock width and thickness. If you have 1/2" square bar and you want to end with 1.5" wide, that's a lot of stretch to make. By the time that 1/2 inch thickness is spread out to 1.5", it will be 3 times as wide and 1/3 the thickness (1/2 divided by 3 is only .17" thick.) There's not much left there for grinding. On the other hand, if you start with 1/2" square and only want to be 1" wide, you will be .25" thick. Plenty of room to grind into.

So there is a lot to consider when choosing the starting stock size. You can do the math, if you like. It will help develop that intuitive knowledge that Lin already has. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//wink.gi f' class='bbc_emoticon' alt=';)' />

Thanks for putting some numbers to it Joshua. This of course is likely the basis of Mike's question and a good one indeed.

Often I perform forging exercises, taking a measured (maybe a cutoff) piece and getting "the most" out of it by choosing what I believe the largest blade/tang size possible for the volume of starting stock.

If I have a design and am driven more by that design, I just simply forge the blade on the end of a bar, by first measuring that bar and then measuring it again after the blade is cut off with the difference being the approximate volume in the blade.

I also sometimes weigh a measured starting piece, then forge a blade and weigh it along the different stages to see how each step affects the weight and material loss.

So, I can understand the kind of approaches that different smiths take when heading into a project. Good stuff here.

Thank you for your replies. I received the answer I was looking for on calculating stock from a friend in the blacksmith club. The answer came from the back of mark aspary book number 3 . I don’t have it in front of me. I’ll share it later.

My second question about the bolister . I know it needs to be in proportion to the knife . Is there a size where it becomes to small? A minimum size.

There's nothing written in stone on the size but I would probably not go under 1/2" round bolster. But that's just me.

In my opinion, the best way to know is to draw the piece and make any adjustment on paper. Side view at least, but top view will help your mind to "see" the 3 dimensional image.

Proportion is vitally important so the drawing will remove any doubts.

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In my opinion, the best way to know is to draw the piece and make any adjustment on paper. Side view at least, but top view will help your mind to "see" the 3 dimensional image.

Proportion is vitally important so the drawing will remove any doubts.

Truer words are rarely said. I almost always work from a full scale design drawing. On pieces too large to fit on 11x17 inch paper, I do a scale drawing down in size so the proportions are set. I do not think there is any substitute for making a drawing before forging. I consider it part of the 6 P's: pre-production planning prevents poor performance. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//wink.gi f' class='bbc_emoticon' alt=';)' />

I absolutely 100% love the ABS forum. I had a question about how big of a knife I could get out of a single piece of round stock, and you geniuses already had that question answered. The wealth of information and experience available here is simply second to none. Except perhaps second to the willingness of the men and women on this forum to share that information.

Thanks as always,

- Evan